Disposable centrifugal separator

ABSTRACT

A disposable, centrifugal separator for separating contaminants from contaminated oil is disclosed. The centrifugal separator has a shroud which defines a first chamber and has a hollow rotor rotatably mounted in the first chamber and defining a second chamber. Oil under pressure is admitted to the second chamber through concentrically arranged tubes or spindles and past a low pressure shut-off valve. The oil flows into the first chamber through tangential reaction nozzles in the rotor to cause contaminants to migrate toward the sidewall of the second chamber under the influence of centrifugal force. The shroud and rotor are permanently closed so that the entire assembly may be discarded when a significant amount of contaminants has been deposited on the sidewall of the second chamber.

Conventional fluid filters, such as oil filters, are basicallymechancial strainers which include a filter element having pores whichtrap and segregate dirt from the fluid. Since the flow through thefilter is a function of the pore size, filter flow will decrease as thefilter pack becomes clogged with dirt. Since the filtration system mustremove dirt at the same rate at which it enters the oil, a cloggedconventional pack cannot process enough oil to keep the dirt level ofthe oil at a satisfactory level. A further disadvantage of somemechanical strainer type filters is that they tend to remove oiladditives. Furthermore, the additives may be depleted to some extent byacting upon trapped dirt in the filter and are rendered ineffective fortheir intended purpose on a working surface in an engine.

Prior art centrifugal filters have been proposed which do not act asmechanical strainers but, rather, remove contaminants from a fluid bycentrifuging. For example, such a filter is shown in U.S. Pat. No. C3,432,091, granted to Beazley. In the Beazley patent, there isillustrated a hollow rotor which is rotatably mounted on a spindle. Thespindle has an axial passageway which conducts oil into the interior ofthe rotor. Tangentially directed outlet ports are provided in the rotorso that the rotor is rotated upon issuance of the fluid therefrom.Solids such as dirt are centrifuged to the sidewalls of the rotor andthe dirt may be later removed by disassembling the rotor and scrapingthe filter cake from the sidewalls.

Such centrifugal filters have oil inlets and outlets through the base ofthe filter, since access to the rotor for cleaning purposes is providedby removing a shroud cover and by then removing the rotor from thespindle. This necessitates a relatively heavy and elaborately machinedbase casting for the centrifugal separator and separator itself isintended to be a permanent installation which is periodically cleaned toremove the sludge buildup.

SUMMARY OF THE INVENTION

This invention relates to a centrifugal separator which is inexpensiveand may be disposed of after use rather than disassembled for cleaning.An inlet is provided at one end of the separator and an axially alignedoutlet is provided at the other end of the separator so that the outwardappearance of the device is very similar to a conventional automotivespin-on crankcase canister filter. It is intended that the filter bereplaced every 50,000 miles; therefore, its construction need not be asrugged or expensive as conventional centrifugal separators.

According to this invention, a closed shroud means defines a firstchamber and a vertically extending spindle is mounted within the shroudand has a permanently sealed, hollow rotor rotatably mounted thereon.The rotor defines a second chamber for receiving contaminated fluids tobe separated and the spindle comprises an inner hollow tube and an outerhollow tube surrounding and spaced from the inner tube. An inlet port isprovided at one end of the inner tube for admitting contaminated fluidsand an outlet port is provided adjacent the other end of the inner tubefor conducting the contaminated fluids to the space between the innerand outer tubes. There is further provided an outlet port adjacent oneend of the outer tube at an end of the tube remote from the other end ofthe inner tube and communicating with the second chamber. A screensurrounds the outer tube and with the outer tube defines a thirdchamber. A baffle separates the outlet port in the outer tube fromdirect communication with the third chamber. The rotor is rotated causecontaminants in contaminated fluids in the second chamber to migratetoward a sidewall of the second chamber under the influence ofcentrifugal force and to be separated from the contaminated fluids. Therotor is rotated by tangentially mounted outlet ports on the rotor influid communication with the third chamber to cause the rotor to rotateupon discharge of fluid from the second chamber to the first chamber.

There is provided a bleeder valve in the first chamber to allow adequatedrainage. The drainage must pass through an outlet fitting which issmaller in flow area than the drain of many prior art arrangements. Thebleeder valve provides an atmospheric reference between the inside andthe outside of the first chamber, thereby venting the suction createdduring drainage.

BRIEF DESCRIPTION OF THE DRAWING

The drawing illustrates a centrifugal filter according to thisinvention, partly in section, and a crankcase mounting fitting adaptedto receive the filter.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the figure, there is illustrated a centrifugalseparator 10 having a sealed shroud 11 which defines a first chamber 12.The shroud 11 comprises a drawn sheet metal can having a lid 13 joinedto the can by a conventional can-type rolled seam 14. The lid 13includes a relatively thick support disc 15 and a relatively thin gaugering 16 welded to the support disc 15. The ring 16 is shaped to retain asealing gasket 17 in a rolled channel 18. An axially aligned inletfitting 19 extends through and is permanently assoicated with thesupport disc 15. An axially aligned outlet fitting 20 is permanentlyaffixed to and extends through the other end of the shroud 11. Theshroud 11 also has attached to it a bleed valve 48 having a light ball50 which remains off its seat by gravity during the filter operation. Iffor some reason the outlet flow is throttled, the first chamber willfill with oil, thereby forcing the ball to its seat and preventing oilfrom leaking to atmosphere. It should be appreciated that the style andconfiguration of the inlet and outlet fittings 19 and 20 are subject toparticular mounting requirements for the separator.

A hollow rotor 21 is rotatably mounted on a spindle assembly 22. Therotor 21 defines a second chamber 23 and comprises a can 24 which isclosed by a base 25 joined to the can 24 by a rolled seam 26. Tangentialand oppositely directed outlet ports 27 and 28 are formed in the base 25in depressions 29.

The spindle assembly 22 comprises an inner tube 30 threaded into theinlet fitting 19 and a concentrically arranged outer tube 31 mounted forthe rotation relative to the inner tube 30 by bearings 32. The rotorassembly 21 is fixed to the rotatable outer tube 31 by snap rings 33.The rotor assembly 21 and the spindle assembly 22 are supported by theinlet fitting 19 which has a neck 34 extending into the outer tube 31and by a heavy spring 35 which has a thrust pad 36 projecting into theinner tube 30. The spring 35 permits fluid access from the first chamber12 to the outlet fitting 20.

Oil enters the inlet fitting 19 from a fitting 37 on a crankcase 38 andflows to an outlet port 39 in the tube 30. The outlet port 39 isnormally closed by a check valve 40 which comprises a spool 41 slidablein the inner tube 30 to a normally closed position across the port 39and held in that position by a spring 42. At a predetermined pressurewithin the tube 30, the spool slides against the bias of the spring 42to open the port 39. Thus, during idling or start-up conditions when theoil pressure is not high, the separator 10 will be bypassed. Oil issuingfrom the outlet port 39 flows through a space between the inner andouter tubes and through outlet ports 43 in the outer tube. There isprovided a baffle 44 around the outlet ports 43 to direct oil into thesecond chamber 23. The oil egresses from the second chamber 23 to thefirst chamber 12 through the reaction nozzles 27 and 28. In order toreach the reaction nozzles 27 and 28, the oil must pass through acylindrical screen 45, which surrounds the outer tube and which, withthe baffle 44 and an annular plate 46, defines a third chamber 47.Desirably, the screen 45 has a mesh which is finer than the nozzleopenings 27 and 28, so that those openings will not be plugged by anylarge particles which may tend to migrate to the third chamber 47. Oilis expelled from the second chamber through the tangentially mountedports 27 and 28, and, since those ports are oppositely directed, theycause the rotor assembly 21 to rotate according to the principle ofHero's engine.

As the rotor assembly 21 rotates, suspended solids migrate to and areretained at the sidewall of the rotor with a force which is dependentupon the running oil pressure of the engine. In time, the dirt particlesand sludge form a rubber mass at the rotor sidewall. After apredetermined number of miles, this mass will accumulate until theentire separator 10 must be replaced.

While the invention has been described in connection with specificembodiments thereof, it is to be clearly understood that this is doneonly by way of example, and not as a limitation to the scope of theinvention as set forth in the objects thereof and in the appendedclaims.

What is claimed is:
 1. In a centrifugal separator for separatingcontaminants from contaminated fluids and being disposable by virtue ofits economical construction, comprising shroud means having ends andintermediate sides defining a first chamber, vertically extendingspindle within said shroud means and having a hollow rotor rotatablymounted thereon, said hollow rotor defining a second chamber forreceiving contaminated fluids to be separated, inlet port means at oneend of said spindle and shroud means, passage means through said spindleto said second chamber, means to rotate said rotor and thereby causecontaminants in contaminated fluids within said second chamber tomigrate toward a sidewall of said second chamber under the influence ofcentrifugal force and to be separated from such contaminated fluids,said means to rotate said rotor comprising tangentially mounted outletport means on said rotor in fluid communication with said second chamberto cause said rotor to rotate upon discharge of fluid from said secondchamber to said first chamber, outlet port means from said firstchamber, in combination therewith the improvement wherein said shroud isa permanently closed assembly substantially fully defining said firstchamber with its sides and ends, said inlet port means at said one endof said spindle being axially aligned with the axis of said spindle,said inlet port including attaching means adapted to releasably attachsaid inlet port to a fitting on a crankcase, said attaching means beingpermanently fixed to said shroud means, said attaching means of saidinlet port being constructed and arranged to be capable of providingsubstantially the sole support of said separator on said crankcasewhereby said separator is readily removed from said crankcase by releasetherefrom of said attaching means, and said outlet port means being atthe other end of said shroud means.
 2. The improvement according toclaim 1, therein said outlet port means is axially aligned with saidinlet port means.
 3. The improvement according to claim 1, wherein thereis provided a sealing ring on said shroud surrounding said inlet portand adapted to form a seal against a crankcase.
 4. A disposablecenrifugal separator for separating contaminants from contaminatedfluids comprising shroud means defining a first chamber, a verticallyextending spindle within said shroud means and having a hollow rotorrotatably mounted thereon, said hollow rotor defining a second chamberfor receiving contaminated fluids to be separated, said spindlecomprising an inner hollow tube and an outer hollow tube surrounding andspaced from said inner tube, an inlet port at one end of said inner tubefor admitting contaminated fluids, a first outlet port adjacent theother end of said inner tube for conducting the contaminated fluids tothe space between the inner and outer tubes, a second outlet portadjacent one end of said outer tube at an end of said tube remote fromsaid other end of said inner tube and communicating with said secondchamber, screen means surrounding said outer tube and with said outertube defining a third chamber within said second chamber, baffle meansseparating said second outlet port from direct communication with saidthird chamber, means to rotate said rotor and thereby cause contaminantsin contaminated fluids within said second chamber to migrate toward asidewall of said second chamber under the influence of centrifugal forceand to be separated from such contaminated fluids, said means to rotatesaid rotor comprising tangentially mounted outlet port means on saidrotor in fluid communication between said third and first chambers tocause said rotor to rotate upon discharge of fluid from said thirdchamber to said first chamber, and a third outlet port from said firstchamber at an end of said shroud opposite said inlet port.
 5. Acentrifugal separator as set forth in claim 4, wherein said first andsecond chambers are permanently sealed.
 6. A centrifugal separatoraccording to claim 4, wherein a pressure-responsive valve is providedbetween the inlet and outlet ports of said inner tube and is openableupon the attainment of a predetermined pressure.
 7. A centrifugalseparator according to claim 6, wherein said pressure-responsive valvecomprises a valve spool slidable within said inner tube andspring-biased to a position blocking the outlet port of said inner tubein the absence of said predetermined pressure.
 8. A centrifugalseparator according to claim 4, wherein said inlet port at said one endof said inner tube is axially aligned with the third outlet port fromsaid first chamber.